With the spread of the Internet, the types of Web browsers for displaying HTML documents acquired via the Internet are increasing. In addition to the types of Web browsers, there are many combinations in consideration of the difference between the version of Web browser and an operating system (OS).
However, the Web browsers have different drawing properties from each other, and have their own expansion function respectively. In addition, regarding HTML, there is a definition having different interpretation for each Web browser. As a result, a display result of an HTML document is different for each Web browser.
Here, a technique of determining whether or not to be the difference of the display result of the HTML document for each Web browser by specifying a display area of each HTML element in the display result of the HTML document for each Web browser and comparing display areas with each other, each of which is specified for each Web browser has been discussed.
Further, a technique of acquiring a partial image cut out from an area, among the display areas on the Web browser, corresponding to the HTML element having a text attribute by using a screen capture function, and then verifying whether or not there are defects on the display such as garbled characters by using the results of character recognition for the partial image has been proposed.
Note that, there is a technique of performing various types of processes by extracting an element having a text attribute from a document image in which a composite document such as an HTML document having images and text mixed is drawn.
Examples of the related art include Japanese Laid-open Patent Publication No. 2010-39815, Japanese Laid-open Patent Publication No. 2016-99793, Japanese Laid-open Patent Publication No. 2015-170979, Japanese Laid-open Patent Publication No. 2008-70831, and Hiroshi TANAKA, Yusaku FUJII, and Eigo SEGAWA, “Automatic Detection of Cross-Browser Presentation Incompatibilities based on the Comparisons of HTML Element Relationships and OCR Results” (PRMU2015-169, 2016-03).